CN112071499A

CN112071499A - Communication cable and method for manufacturing the same

Info

Publication number: CN112071499A
Application number: CN202010437006.0A
Authority: CN
Inventors: 石田丰; 高原知之; 西馆步
Original assignee: Hitachi Metals Ltd
Current assignee: Proterial Ltd
Priority date: 2019-06-11
Filing date: 2020-05-21
Publication date: 2020-12-11
Also published as: JP6941286B2; JP2020202106A; DE102020115427A1; CN117747183A; JP2021103693A; JP6870705B2

Abstract

The invention provides a communication cable and a manufacturing method thereof, wherein the communication cable realizes improvement of transmission characteristics when high-speed signals are transmitted. A communication cable (1) is provided with a plurality of shielded core wires (4), wherein the shielded core wires (4) are provided with: a core wire (2) having an insulator (22) that covers the periphery of each of the one or more conductors (21) or collectively; and a shielding tape (3) longitudinally wound so as to cover the periphery of the core wire (2), wherein in the communication cable (1), each of the plurality of tape-shielded core wires (4) is arranged so that a winding end side end portion (3a) is positioned radially outward of the communication cable (1) with respect to the center position of the core wire (2), and the winding end side end portion (3a) is one end portion in the width direction of the shielding tape (3) and is positioned outward of the longitudinal winding.

Description

Communication cable and method for manufacturing the same

Technical Field

The present invention relates to a communication cable such as a LAN cable and a method for manufacturing the same.

Background

Conventionally, as a communication cable, a communication cable is known in which a plurality of shielded core wires, each having a shielding tape spirally wound around a twisted pair, are twisted, and a sheath is provided so as to collectively cover the circumference of the twisted core wires. As the shield tape, a shield tape in which a metal layer is formed on one surface of a resin layer is used.

In recent years, communication speed has been increasing, and for example, in LAN (Local Area Network) cables, communication cables applicable to category 7 or above category 7A, category 8, and the like in accordance with ISO/IEC11801 have been demanded. However, in the above-described communication cable, a current flows through an end portion of the metal layer of the shield tape wound in a spiral shape, and crosstalk occurs, and particularly, in the case of a high-speed signal, transmission characteristics such as a crosstalk attenuation amount deteriorate, and thus it is difficult to satisfy the above-described standard. Therefore, a structure is proposed in which the shield tape is longitudinally wound in the tape shield core wire.

Patent document 1 is information on a prior art document related to the present invention.

Documents of the prior art

Patent document

Patent document 1: specification of U.S. Pat. No. 2015/0096783

Disclosure of Invention

Problems to be solved by the invention

However, sufficient transmission characteristics may not be obtained by simply winding the shield tape in the longitudinal direction.

Accordingly, an object of the present invention is to provide a communication cable having improved transmission characteristics when transmitting a high-speed signal, and a method for manufacturing the same.

Means for solving the problems

In order to solve the above-described problems, the present invention provides a communication cable including a plurality of shielded core wires each having a core wire and a shield tape longitudinally wound so as to cover a periphery of the core wire, the core wire having an insulator covering or collectively covering a periphery of one or more conductors, wherein each of the plurality of shielded core wires is arranged such that a winding end side end portion, which is one end portion in a width direction of the shield tape and is positioned outside the longitudinal winding, is positioned radially outside the communication cable more than a center position of the core wire.

In order to solve the above-described problems, the present invention provides a method for manufacturing a communication cable including a plurality of shielded core wires each including a core wire and a shield tape longitudinally wound so as to cover a periphery of the core wire, the core wire including an insulator covering or collectively covering a periphery of one or more conductors, the method including rotating the shielded core wires guided out from the plurality of dies together in a circumferential direction using a plurality of dies to form an aggregate, the dies including a pair of guide grooves for guiding both end portions of the shield tape in a width direction, the dies being configured to: the shield tape is gradually deformed into a cylindrical shape at both ends in the width direction thereof by the guide grooves, and the shield tape is longitudinally wound around the core wire to form the tape shield core wire, and the winding end side end portion of the plurality of tape shield core wires, which is one end in the width direction of the shield tape and is positioned outside the longitudinal winding, is arranged radially outward of the communication cable from the center position of the core wire when the assembly is formed by adjusting the installation angles of the plurality of dies, respectively.

Effects of the invention

According to the present invention, a communication cable and a method for manufacturing the same can be provided, in which transmission characteristics are improved when high-speed signals are transmitted.

Drawings

Fig. 1 is a view showing a communication cable according to an embodiment of the present invention, (a) is a cross-sectional view showing a cross-section of the communication cable perpendicular to a longitudinal direction, and (b) is a perspective view showing an end portion thereof.

Fig. 2 is a cross-sectional view of a shielding tape.

Fig. 3 is an explanatory diagram for explaining the direction of crosstalk of the shielded core wire.

Fig. 4(a) is a schematic configuration diagram of a stranding device used in the manufacture of a communication cable, (b) is a schematic diagram of a tape unit thereof, and (c) is a perspective view showing a mold of the tape unit.

Fig. 5 is a sectional view showing the arrangement of the mold.

Fig. 6 is a graph showing near-end crosstalk attenuation characteristics of the communication cable according to the embodiment.

Fig. 7(a) is a cross-sectional view showing a cross-section perpendicular to the longitudinal direction of the communication cable of the comparative example, and (b) is a graph showing the attenuation characteristics of near-end crosstalk.

Description of the symbols

1 … communication cable, 2 … core wire, 21 … conductor, 22 … insulator, 221 … foaming layer, 222 … non-foaming layer, 23 … insulated wire, 3 … shielding tape, 3a … winding end side end, 31 … resin layer, 32 … metal layer, 4 … tape shielding core wire, 5 … aggregate, 6 … metal shielding layer and 7 … sheath.

Detailed Description

[ embodiment ]

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a view showing a communication cable according to the present embodiment, (a) is a cross-sectional view showing a cross-section of the communication cable perpendicular to a longitudinal direction, and (b) is a perspective view showing an end portion thereof.

As shown in fig. 1(a) and (b), the communication cable 1 includes: a plurality of core wires 2 each having one or more conductors 21 and insulators 22 covering the conductors 21 individually or collectively; a shield tape 3 longitudinally wound around the core wire 2; a metal shield layer 6 that covers an aggregate 5 obtained by twisting a plurality of shielded wires 4 each of which is formed by covering the core wire 2 with a shield tape 3; and a sheath 7 covering the periphery of the metal shield layer 6.

The communication cable 1 is used as a LAN cable for railway vehicles, a LAN cable for transmitting and receiving large-capacity data in a data center, and the like, for example.

In the present embodiment, the core wire 2 includes a pair of insulated wires 23 each including 1 conductor (a stranded conductor obtained by stranding a plurality of metal wires 21 a) 21 covered with an insulator 22, and is formed of a twisted pair obtained by twisting the pair of insulated wires 23. However, the core wire 2 is not limited to this, and may have a double-core collectively-covered structure in which the pair of conductors 21 arranged in parallel are collectively covered with the insulator 22, for example, or may have only 1 insulated wire 23.

The conductor 21 is formed of a stranded conductor obtained by stranding a plurality of metal wires 21 a. As the metal wire 21a, a soft copper wire made of pure copper, or a metal wire obtained by plating a soft copper wire made of pure copper with a metal such as tin or silver can be used. The conductor 21 is not limited to this, and may be a single-wire conductor.

The insulator 22 has a foamed layer 221 made of a foamed resin covering the periphery of the conductor 21, and a non-foamed layer 222 made of a non-foamed resin covering the periphery of the foamed layer 221. As the foaming resin constituting the foaming layer 221, for example, foamed polyethylene can be used. As the non-foamed resin constituting the non-foamed layer 222, for example, non-foamed polyethylene can be used. The insulator 22 is not limited to this, and may be made of a material having a relative dielectric constant of 2.5 or less, for example, a fluorine resin such as FEP (tetrafluoroethylene-hexafluoropropylene copolymer).

As shown in fig. 2, the shield tape 3 has a resin layer 31 and a metal layer 32 formed on one surface of the resin layer 31. In the present embodiment, the resin layer 31 is made of polyester such as PET (polyethylene terephthalate). Further, the metal layer 32 is made of aluminum which is lightweight and low cost. The shield tape 3 is longitudinally wound so as to cover the respective peripheries of the plurality of core wires 2 with the metal layer 32 as the outer side. The method of winding the shield tape 3 and the like will be described in detail later.

The shielded core wire 4 is formed by longitudinally winding a shielding tape 3 around the core wire 2. Here, a case where 4 shielded wires 4 are used will be described, but the number of shielded wires 4 is not limited to this. In the present embodiment, 4 core wires 2, that is, 4 twisted pairs are used, but the twist pitches of the 4 twisted pairs are preferably different from each other. This can suppress the crosstalk attenuation amount.

The 4 shielded wires 4 are twisted with each other to form an aggregate 5. The aggregate 5 is twisted at a relatively long twist pitch of 70mm to 140 mm. By setting the twist pitch of the aggregate 5 to 70mm or more, the electrical length of the communication cable 1 can be shortened to shorten the propagation delay time, and further, the core wires 2 can be suppressed from being tightened to collapse the foam layer 221, and deterioration of the transmission characteristics can be suppressed. Further, as described in detail later, in the present embodiment, since each of the tape shield core wires 4 is twisted in accordance with the twist of the assembly 5, if the twist pitch of the assembly 5 is short, wrinkles or the like are generated in the shield tape 3, and there is a possibility that the transmission characteristics are deteriorated, but by setting the twist pitch of the assembly 5 to 70mm or more, the generation of wrinkles in the shield tape 3 can be suppressed, and the deterioration of the transmission characteristics can be suppressed. Further, by setting the twist pitch of the aggregate 5 to 140mm or less, it is possible to suppress concentration of a load on one shielded core wire 4 when the communication cable 1 is bent or the like, and it is possible to suppress deterioration of transmission characteristics and shortening of the cable life. Further, the orientation and relative positional relationship of the respective shielded wires 4 can be easily maintained by twisting, and the positional relationship between the winding end side end portions 3a described later and the like can be maintained.

By setting the twist pitch of the assembly 5 to 70mm or more and 140mm or less in this way, it is possible to suppress stress on the shielded core wire 4, suppress collapse of the foam layer 221, and suppress generation of wrinkles in the shield tape 3, and suppress deterioration of transmission characteristics due to bending, and to maintain the orientation and position of the winding end side end portion 3a (described later) of the shield tape 3 with the shielded core wire 4. The twisted pair used as the core 2 has a twist pitch of, for example, 14mm to 20 mm. The twist pitch of the aggregate 5 is 4 times or more the twist pitch of the twisted pair serving as the core 2.

The metal shield layer 6 is formed to cover the periphery of the aggregate 5. The metal shield layer 6 is in contact with and electrically connected to the metal layer 32 of the shield tape 3 in each tape shield core wire 4, and is configured to have the same potential.

In the present embodiment, the metal shield layer 6 is formed of a braided shield in which metal wires are braided. The metal shield layer 6 is less likely to fasten a member (here, the aggregate 5) located radially inward of the metal shield layer 6 than a transverse wound shield in which a metal wire is arranged in a spiral shape, for example. In the present embodiment, the assembly 5 is not fastened by appropriately adjusting the inner diameter of the metal shield layer 6. Thus, even when the insulating body 22 includes the foamed layer 221, the foamed layer 221 can be prevented from collapsing, and deterioration of transmission characteristics can be prevented. In addition, the shielded core wire 4 can move relatively freely in the metal shield layer 6, and the communication cable 1 is easily bent. Further, since a gap is maintained between the shielded wires 4, that is, an air layer having a low relative permittivity is maintained, the attenuation amount can be further suppressed. Although not shown in fig. 1(a), the shield tape 3 actually enters the gap between the tape shield cores 4, and the cross-sectional shape of the shield tape 3 does not become a circular shape.

In the present embodiment, the sheath 7 is made of polyolefin. As the jacket 7, a jacket made of polyvinyl chloride (PVC) or fluororesin may be used. When flame retardancy is required, it is effective to use a sheath made of ethylene-vinyl acetate copolymer (EVA) as the sheath 7. In addition, 100 parts by mass or more and 250 parts by mass or less of a metal hydroxide such as aluminum hydroxide or magnesium hydroxide as a flame retardant may be added to 100 parts by mass of the base resin in the sheath 7. Further, an acid-modified polyolefin or the like may be added to the sheath 7. In order not to fasten the aggregate 5, the sheath 7 may be formed by tube extrusion. The outer diameter of the sheath 7, i.e. the outer diameter of the communication cable 1, is for example 8.8 mm.

(details of the method of winding the shielding tape 3, etc.)

As a result of studies by the present inventors, when the shield tape 3 is spirally wound around the core wire 2 (twisted pair), the resin layer 31 is periodically arranged in the cable longitudinal direction, and therefore, when a high-speed signal is transmitted, crosstalk occurs in all directions in the circumferential direction from the resin layer 31. On the other hand, when the shield tape 3 is longitudinally wound as in the present embodiment, as shown in fig. 3, it is found that crosstalk occurs from one end portion in the width direction of the shield tape 3 and an end portion located on the outer side of the longitudinal winding (hereinafter, referred to as a winding end side end portion 3a) when a high-speed signal is transmitted. Accordingly, the winding end side ends 3a of the shield tapes 3 in each tape shield core wire 4 are sufficiently separated from each other, whereby the crosstalk attenuation amount can be suppressed.

Therefore, in the present embodiment, each of the plurality of shielded wires 4 is arranged such that the winding end side end portion 3a of the shield tape 3 is positioned radially outward of the center position (central axis) of the wire 2. That is, as shown in fig. 1(a), each shielded wire 4 is disposed such that the winding end side end portion 3a is disposed outside a circle a passing through the center positions of the 4 wires 2. Thus, compared to the case where the winding end side end portions 3a are arranged radially inward of the center position (circle a) of the core wire 2 in each shielded core wire 4, the winding end side end portions 3a as crosstalk generation positions can be separated from each other, and the crosstalk attenuation amount can be suppressed, thereby improving the transmission characteristics. In addition, when actually manufacturing the communication cable 1, the positional deviation of each core wire 2 is also considered. In this case, the winding end side end portion 3a may be disposed further outside than a perfect circle centered on the center position (cable center) of the communication cable 1 and passing through the center position of the core wire 2 closest to the cable center among the 4 core wires 2 in a cross-sectional view perpendicular to the longitudinal direction.

In order to further suppress the crosstalk attenuation amount, it is more preferable to dispose the winding end side end portion 3a further radially outward, and it is more preferable to dispose each shielded core wire 4 so that the winding end side end portion 3a is disposed radially outward of the core wire 2. That is, the shield tape 3 is wound around the shielded core wires 4 such that the winding end side end portion 3a is positioned radially outward (radially outward of the communication cable 1) of the core wire 2. In the present embodiment, each shielded core wire 4 is disposed such that the winding end side end 3a of the shielded wire 3 is positioned radially outward of the circle B circumscribing the 4 core wires 2. In addition, when actually manufacturing the communication cable 1, the positional deviation of each core wire 2 is also considered. In this case, in a cross-sectional view perpendicular to the longitudinal direction, the winding end side end portion 3a may be disposed further outside than a perfect circle that is centered on the center position (cable center) of the communication cable 1 and that circumscribes the core wire 2 closest to the cable center among the 4 core wires 2.

The winding end side ends 3a of the shield tapes 3 of the respective shielded wires 4 may be spaced apart from each other by 2.5mm or more. This is because, if the distance (linear distance in a cross-sectional view perpendicular to the longitudinal direction) between the winding end side end portions 3a of the shield tapes 3 of the respective shielded wires 4 is less than 2.5mm, the crosstalk attenuation amount increases, and there is a possibility that the transmission characteristics deteriorate.

In the present embodiment, each of the plurality of shielded wires 4 is disposed such that the winding end side end portion 3a of the shield tape 3 faces the gap C formed between the circumferentially adjacent shielded wire 4 and the metal shield layer 6. In the

communication cable

1, 4 shielded core wires 4 are arranged in the circumferential direction, and therefore, there are 4 gaps C, but the winding end side end portions 3a of the shield tapes 3 of the respective shielded core wires 4 are arranged so as to face the different gaps C.

Further, without being limited thereto, the winding end side end portion 3a of the shield tape 3 of each shielded core wire 4 may face the metal shield layer 6. From the viewpoint of reducing the crosstalk attenuation amount, it is more preferable that the winding end side end portion 3a of the shield tape 3 of each tape shield core 4 does not face the winding end side end portion 3a of the shield tape 3 of another tape shield core 4 (the winding end side end portion 3a does not face the winding end side end portion 3a of the shield tape 3 of another tape shield core 4). In the present embodiment, the winding end side end portion 3a of the shield tape 3 of each shielded core wire 4 faces the metal shield layer 6 positioned between the adjacent shielded core wires 4.

The winding end side portions 3a of the shield tapes 3 of the respective shielded wires 4 are preferably spaced as far as possible, and are preferably arranged at substantially equal intervals in the circumferential direction. In other words, the winding end side end 3a of the shield tape 3 with the shield core wire 4 is preferably arranged at a position rotationally symmetrical to the cable center by substantially 90 degrees.

The shield cores 4 are twisted in accordance with the twisting of the assembly 5, and the relative positional relationship of the winding end side end portions 3a of the shield tapes 3 of the shield cores 4 is substantially constant regardless of the longitudinal position. Therefore, when the assembly 5 is visually observed with the sheath 7 and the metal shield layer 6 removed, the winding end side end portion 3a of each of the 4 shielded core wires 4 is exposed to the outside. That is, each shielded core wire 4 is disposed so that the winding end side end portion 3a thereof is visible from the outside.

Further, it is preferable that the winding directions of the shield tapes 3 of the plurality of shielded core wires 4 are the same. This is because, since crosstalk enters the core wire 2 from the winding end side end portion 3a, if the tape shield core wire 4 in which the winding direction of the shield tape 3 is in the opposite direction is included, the winding end side end portions 3a of the shield tapes 3 of the tape shield core wires 4 adjacent in the circumferential direction face each other in the circumferential direction, and there is a possibility that the crosstalk attenuation amount becomes large. The winding direction of the shield tape 3 here is a direction in which the shield tape 3 rotates around the core wire 2 from an end opposite to the winding end side end 3a in the width direction of the shield tape 3 to the winding end side end 3a when viewed from one end of the tape shield core wire 4.

The shield tape 3 is wound around the core wire 2 so that the circumference of the core wire 2 is 1.3 to 1.5 cycles inclusive. If the winding of the shield tape 3 is less than 1.3 turns around the core wire 2, the length of the overlapping portion becomes too short, and the overlapping portion opens for some reason, and there is a possibility that crosstalk increases. Further, the shield tape 3 is longitudinally wound around the core wire 2 over 1.5 cycles, which makes the manufacturing difficult, increases the cost, and makes the communication cable 1 heavy. When the shield tape 3 is wound around the core wire 2 for 1.3 turns, the overlapping length is about 23% of the width of the shield tape 3. Further, when the shield tape 3 is wound around the core wire 2 for 1.5 turns, the overlapping portion length is about 33% of the width of the shield tape 3. Accordingly, the length of the overlapping portion of the shield tape 3 may be 23% or more and 33% or less of the width of the shield tape 3. In the present embodiment, each of the plurality of shielded wires 4 is disposed so that an overlapping portion (a portion where the shield tape 3 is double-layered) where the shield tape 3 overlaps and the metal shield layer 6 face each other in the radial direction. That is, the overlapping portion of the shield tape 3 with the shield core wire 4 is located on the metal shield layer 6 side rather than the center side of the communication cable 1.

The thickness of the metal layer 32 of the shield tape 3 may be 30 μm or more. This is because if the thickness of the metal layer 32 is less than 30 μm, there is a possibility that it will break during manufacturing, and further, there is a possibility that the shape of the shield tape 3 cannot be maintained in a state where the core wire 2 is wound (the winding end side end portion 3a will be opened after winding). In the present embodiment, the thickness of the metal layer 32 is set to 38 μm, and the thickness of the resin layer 31 is set to 12 μm.

(method of manufacturing communication Cable 1)

In manufacturing the communication cable 1, first, the foamed layer 221 and the non-foamed layer 222 are simultaneously coated around the conductor 21 to form the insulated wire 23. After that, the aggregation 5 is formed using the twisting device 40 shown in fig. 4 (a). Specifically, a pair of drums 41 around which the insulated wires 23 are wound are provided in the output portion 42, and the insulated wires 23 are output from the two drums 41 while rotating the pair of drums 41, thereby forming the core wire 2 formed of a twisted pair. Here, 4 output portions 42 are provided. The 4 core wires 2 fed out from the 4 feeding portions 42 are introduced into the take-up portion 43.

As shown in fig. 4(b), in the tape winding portion 43, the shield tape 3 fed from the bobbin 43a is fed to the die 44 together with the core wire 2 fed from the feeding portion 42 while being given tension via the plurality of rollers 43 b. In fig. 4(b), the core wire 2 is shown by a broken line. In fig. 4(b), although only the paths of 1

bobbin

43a and 1 shielding tape 3 are representatively shown, actually, 4 bobbins 43a are provided so as to correspond to 4 core wires 2, and the shielding tape 3 is conveyed from each bobbin 43a to the corresponding die 44 via a plurality of rollers 43 b.

As shown in fig. 4 c, the mold 44 includes a cylindrical body part 441 and a tape guide 442 provided on the inlet side (the introducing side of the shield tape 3 and the core wire 2) of the body part 441. The tape guide 442 has a pair of guide grooves 442a that guide both ends of the shield tape 3 in the width direction, and the tape guide 442 is configured to: the both end portions of the shield tape 3 in the width direction gradually deform the shield tape 3 into a cylindrical shape by the guide grooves 442a, thereby longitudinally winding the shield tape 3 around the core wire 2. By appropriately adjusting the attachment angle of the tape guide 442, the entry angle of the shield tape 3 into the main body 441 can be kept constant at a desired angle, and the position of the winding end side end portion 3a of the shield tape 3 can be adjusted to a desired position. The attachment angle of the tape guide 442 herein means the attachment angle in the circumferential direction of the main body 441.

More specifically, as shown in fig. 5, the tape guides 442 of the respective molds 44 are arranged so as to be rotationally symmetrical at 90 degrees. In fig. 5, each die 44 is shown in a cross-sectional view along the line C-C in fig. 4 (C). In the present embodiment, the core wires 2 are introduced into the mold 44 in a state of facing the widthwise central portion of the shield tape 3. In the present embodiment, since the winding end side end portion 3a is disposed on the opposite side to the position of the introduced shield tape 3 with the core wire 2 interposed therebetween, the installation angle of the tape guide 442 is adjusted so that the shield tape 3 is inside and the core wire 2 is outside. The molds 44 are arranged close to each other and fixed by a fixing ring, not shown, in a state where the attachment angle of the tape guide 442 is appropriately adjusted.

The 4 shielded core wires 4 led out from the respective molds 44 are guided into a cylindrical collecting guide device 46 to be bundled (collected), and are conveyed to the winding portion 45. More specifically, the winding unit 45 rotates and twists the 4 belt shielded core wires 4 passing through the collection guide 46 in the circumferential direction to form the aggregate 5, and the formed aggregate 5 is conveyed to the winding unit 45. Further, if the 4 belt shield cores 4 are twisted without using the collection guide 46, it is difficult to control the position of the winding end side end portion 3a of the shield belt 3 of each belt shield core 4, and therefore, in the present embodiment, the 4 belt shield cores 4 are collected by the collection guide 46 and then twisted to form the aggregate 5. The collecting guide 46 also serves to prevent the influence of the rotation caused by the winding portion 45 from being transmitted to the mold 44 side.

Returning to fig. 4(a), the winding unit 45 includes a drum 45a for winding the assembly 5 and a rotating mechanism 45b for winding the 4 belt shielding wires 4 around the drum 45a while rotating them all in the circumferential direction. The assembly 5 is formed by rotating (twisting) the 4 tape shield core wires 4 bundled by the collection guide 46 of the tape winding portion 43 in the circumferential direction by the rotating mechanism 45 b. As described above, since the collective guide device 46 is used, the twisting can be performed while maintaining the relative positional relationship of the winding end side end portions 3a of the shield tapes 3 of the respective shielded core wires 4. The formed aggregate 5 is wound around the drum 45a by the rotation of the rotating mechanism 45 b.

Then, a metal shield layer 6 made of a braided shield is formed around the assembly 5 wound around the drum 45a, and a sheath 7 is formed around the metal shield layer 6 by tube extrusion, thereby obtaining the communication cable 1.

(Crosstalk attenuation characteristics of communication cable 1)

As an example, the near-end crosstalk attenuation amount characteristic of the communication cable 1 according to the present embodiment is obtained by simulation. The obtained near-end crosstalk attenuation characteristics are shown in fig. 6. Fig. 6 also shows standard values required for the LAN cables of category 7. As shown in fig. 6, it is understood that the communication cable 1 of the embodiment provides a near-end crosstalk attenuation amount having a likelihood with respect to a standard value even for a high-speed signal of 100MHz or more, and obtains excellent crosstalk attenuation amount characteristics.

For comparison with the present embodiment, the characteristics of the near-end crosstalk attenuation amount were obtained by simulation in the same manner as in the example for the communication cable 60 of the comparative example shown in fig. 7 (a). The communication cable 60 of the comparative example has the same configuration as the communication cable 1 of the embodiment, except that the winding end side end portion 3a of the shield tape 3 with each shield core wire 4 is disposed on the cable center side (radially inward of the communication cable 1 from the center position of the core wire 2). Fig. 7(b) shows the obtained near-end crosstalk attenuation characteristics.

As is clear from a comparison between fig. 7(b) and fig. 6, in the communication cable 60 of the comparative example, the near-end crosstalk attenuation amount increases for high-speed signals of 100MHz or more as compared with the communication cable 1 of the example, and the likelihood of the near-end crosstalk attenuation amount with respect to the standard value decreases although the near-end crosstalk attenuation amount satisfies the standard value.

(action and Effect of the embodiment)

As described above, in the communication cable 1 according to the present embodiment, each of the plurality of shielded wires 4 is disposed such that the winding end side end portion 3a, which is one end in the width direction of the shield tape 3 wound in the longitudinal direction and is located outside the longitudinal winding, is located radially outward of the communication cable 1 from the center position of the core wire 2.

Thus, compared to the case where the winding end side end portions 3a of the shield tapes 3 are disposed further inward in the radial direction of the communication cable 1 than the center position of the core wires 2, the distance between the winding end side end portions 3a of the shield tapes 3 with the shield core wires 4 can be secured to be large, and the transmission characteristics such as the crosstalk attenuation amount when high-speed signals of 100MHz or more are transmitted can be improved. As a result, the communication cable 1 can satisfy the characteristics required for the LAN cables of type 7 or more (e.g., type 7A, type 8).

(summary of the embodiment)

Next, the technical ideas grasped in the above-described embodiments will be described with reference to the symbols and the like in the embodiments. However, the reference numerals and the like in the following description do not limit the components in the claims to those specifically shown in the embodiments.

[1] A communication cable (1) is provided with a plurality of shielded core wires (4), wherein the shielded core wires (4) comprise: a core wire 2 having insulators 22 covering the peripheries of the one or more conductors 21, respectively or collectively; and a shield tape 3 longitudinally wound so as to cover the periphery of the core wire 2, wherein in the communication cable 1, the plurality of tape shield core wires 4 are each arranged so that a winding end side end portion 3a is positioned radially outward of the communication cable 1 with respect to a center position of the core wire 2, and the winding end side end portion 3a is one end portion in a width direction of the shield tape 3 and is positioned outward of the longitudinal winding.

[2] According to the communication cable 1 described in item [1], the winding end side ends 3a of the shield tapes 3 of the plurality of shielded core wires 4 are spaced apart from each other by 2.5mm or more.

[3] According to the communication cable 1 of [1] or [2], the winding directions of the shield tapes 3 of the plurality of shielded core wires 4 are the same.

[4] According to the communication cable 1 of any one of [1] to [3], the plurality of shielded wires 4 are arranged such that the winding end side end portion 3a of the shielding tape 3 is positioned radially outward of the core wires 2.

[5] The communication cable 1 according to any one of [1] to [4], which includes a metal shield layer 6 collectively covering the peripheries of the plurality of shielded core wires 4, wherein the plurality of shielded core wires 4 are arranged such that a winding end side end portion 3a of the shield tape 3 faces a gap C between the metal shield layer 6 and the shielded core wire 4 adjacent in the circumferential direction.

[6] The communication cable 1 according to any one of [1] to [5], wherein a twist pitch of the aggregate 5 is 70mm or more and 140mm or less.

[7] The communication cable 1 according to any one of [1] to [6], wherein the shielding tape 3 includes a resin layer 31 and a metal layer 32 formed on one surface of the resin layer 31, the metal layer 32 of the shielding tape 3 is made of aluminum, and a thickness of the metal layer 32 is 30 μm or more.

[8] The communication cable 1 according to any one of [1] to [7], which includes a metallic shield layer 6 collectively covering peripheries of the plurality of shielded core wires 4, wherein the metallic shield layer 6 is a braided shield formed by braiding metallic wires, and the insulator 22 of the core wire 2 includes a foamed layer 221 made of a foamed resin.

[9] A method for manufacturing a communication cable 1 having a plurality of shielded core wires 4, the shielded core wires 4 comprising: a core wire 2 having insulators 22 covering the peripheries of the one or more conductors 21, respectively or collectively; and a shield tape 3 longitudinally wound so as to cover the periphery of the core wire 2, wherein the manufacturing method forms the aggregate 5 by collectively rotating the plurality of tape shield core wires 4 led out from the plurality of dies 44 in the circumferential direction using a plurality of dies 44, the dies 44 have a pair of guide grooves 442a that guide both end portions of the shield tape 3 in the width direction, and the dies 44 are configured such that: the shield tape 3 is gradually deformed into a cylindrical shape at both ends in the width direction of the shield tape 3 by the guide grooves 442a, and the shield tape 3 is longitudinally wound around the core wire 2 to form the tape shield core wire 4; by adjusting the installation angles of the plurality of dies 44, respectively, when the assembly 5 is formed, the winding end side end portion 3a of the plurality of tape-shielded core wires 4, which is one end in the width direction of the shielding tape 3 and is located outside the longitudinal winding, is arranged further outward in the radial direction of the communication cable 1 than the center position of the core wire 2.

[10] According to the method for manufacturing a communication cable described in [9], the plurality of shielded wires 4 led out from the plurality of molds 44 are guided to the collecting guide 46 to be collected, and the plurality of shielded wires 4 collected by the collecting guide 46 are collectively rotated in the circumferential direction, thereby forming the assembly 5.

The embodiments of the present invention have been described above, but the embodiments described above do not limit the invention according to the claims. Note that all combinations of the features described in the embodiments are not necessarily essential to means for solving the problems of the invention.

The present invention can be implemented with appropriate modifications within the scope not departing from the gist thereof. For example, although not mentioned in the above embodiment, in the tape-shielded core wire 4, the multilayer shielding tape 3 may also be wound by longitudinal winding. For example, when 2 layers of the shield tape 3 are wound, the amount of crosstalk attenuation can be further suppressed by setting the winding directions of the 1 st layer and the 2 nd layer to be opposite directions. In this case, the winding end side end 3a of the shield tape 3 wound on the outermost side may be positioned radially outward of the center position of the core wire 2 with respect to the communication cable 1.

Claims

1. A communication cable is provided with a plurality of shielded core wires, the shielded core wires having: a core wire having an insulator covering the periphery of one or more conductors, respectively or collectively; and a shielding tape longitudinally wound in a manner to cover the circumference of the core wire,

in the communication cable, the plurality of tape shield core wires are arranged such that a winding end side end portion, which is one end in a width direction of the shield tape and is located outside a longitudinal winding, is located radially outside the communication cable than a center position of the core wires.

2. The communication cable according to claim 1, wherein winding end side ends of the shielding tapes of the plurality of shielded core wires are spaced apart from each other by 2.5mm or more.

3. The communication cable according to claim 1 or 2, wherein winding directions of the shield tapes of the respective plurality of shielded core wires are the same direction.

4. The communication cable according to any one of claims 1 to 3, wherein each of the plurality of shielded core wires is disposed such that a winding end side end portion of the shielding tape is positioned radially outward of the core wires.

5. The communication cable according to any one of claims 1 to 4, comprising a metal shield layer collectively covering peripheries of the plurality of shielded core wires,

the plurality of shielded wires are arranged such that winding end side ends of the shielding tapes face gaps between the plurality of shielded wires and the metal shielding layer adjacent to each other in the circumferential direction.

6. The communication cable according to any one of claims 1 to 5, wherein a twist pitch of an aggregate in which the plurality of shielded core wires are twisted is 70mm or more and 140mm or less.

7. The communication cable according to any one of claims 1 to 6, wherein the shielding tape has a resin layer and a metal layer formed on one surface of the resin layer,

the metal layer of the shielding tape is composed of aluminum,

the thickness of the metal layer is more than 30 μm.

8. The communication cable according to any one of claims 1 to 7, comprising a metal shield layer collectively covering peripheries of the plurality of shielded core wires, wherein the metal shield layer is a braided shield formed by braiding metal wires,

the insulator of the core wire includes a foamed layer composed of a foamed resin.

9. A method for manufacturing a communication cable having a plurality of shielded core wires, the shielded core wires comprising: a core wire having an insulator covering the periphery of one or more conductors, respectively or collectively; and a shielding tape longitudinally wound in a manner to cover the circumference of the core wire,

the manufacturing method uses a plurality of dies to rotate a plurality of shielded core wires led out from the plurality of dies together in a circumferential direction to form an aggregate,

the mold has a pair of guide grooves that guide both ends of the shield tape in the width direction, and is configured such that: the both end portions in the width direction of the shield tape gradually deform the shield tape into a cylindrical shape by the guide grooves to longitudinally wind the shield tape around the core wire to form the tape shield core wire,

by adjusting the installation angles of the plurality of dies, respectively, when the assembly is formed, a winding end side end portion of the plurality of shielded core wires, which is one end in the width direction of the shielding tape and is located outside the longitudinal winding, is arranged further outward in the radial direction of the communication cable than a center position of the core wire.

10. The method for manufacturing a communication cable according to claim 9, wherein a plurality of the shielded wires led out from the plurality of molds are guided to a collecting guide device to be collected,

the assembly is formed by collectively rotating the plurality of shielded core wires assembled by the assembly guide device in the circumferential direction.